<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box {
            width: 200px;
            background-color: salmon;
            margin: 0 auto;
            /* overflow: hidden; */
        }
        .box .box1 {
            width: 80px;
            height: 80px;
            background-color: rosybrown;
            float: left;
        }
        .box .box2 {
            width: 100px;
            height: 100px;
            background-color: rosybrown;
            float: left;
        }
        .clear {
            clear: both;
        }
        .box3 {
            /* clear: both; */
            height: 130px;
            background-color: darkgrey;
        }
        .clearfix:after {
            content: "";
            display: block;
            height: 0;
            clear: both;
            visibility: hidden;
        }
        .clearfix { /* IE6, 7专有 */
            *zoom: 1;
        }
    </style>
</head>
<body>
    <div class="box clearfix">
        <div class="box1">1234</div>
        <div class="box2">2222</div>
        <div class="box2">2222</div>
        <div class="box2">2222</div>
        <!-- <div class="clear"></div> -->
    </div>
    <div class="box3">2222</div>
</body>
</html>